1. Field of the Invention
The present invention relates to an ink-jet head that conducts recordings by ejecting ink to a recording medium, and more specifically to an ink-jet head in which a constriction whose passage width is narrower than that of a pressure chamber is formed between an ink chamber and the pressure chamber and which changes the pressure of ink in the pressure chamber so that the ink is ejected through a corresponding nozzle.
2. Description of Related Art
Ink-jet heads employed in ink-jet printers or the like, include one which has an ink chamber for containing ink, pressure chambers supplied with ink from the ink chamber, nozzles communicating with the respective pressure chambers, and which changes the pressure of ink in the pressure chambers so that the ink is ejected through the nozzles. In such a head, provided is an actuator applied with a drive pulse to thereby change the pressure of ink in the pressure chambers, which is a known technique.
Recent years see a demand for high-speed and high-quality printings, and various techniques have been proposed in order to realize such printings. In an example of such techniques, in an ink-jet head having the aforementioned structure, a flow resistance throughout an ink passage and a flow resistance of a constriction formed between the ink chamber and the pressure chamber are brought into focus, and a ratio between these two flow resistances is kept within a predetermined range in order to avoid spoiling ejection stability even in a high-speed printing (see U.S. Pat. No. 6,736,493).
However, speed and quality of printings become higher and higher today, and therefore there arises a need to develop an ink-jet head capable of such a higher-speed and higher-quality printing. In the ink-jet head having the aforementioned structure, particularly, it is required that stable ejection is maintained even if a frequency of the drive pulse that is applied to the actuator is variously changed or a temperature environment where the head is used is variously changed.